Our goals for the next year include: continuation of the analysis of F and Le interferon production on induction of diploid fibroblasts with Newcastle disease virus (differential control of synthesis of the two interferons, kinetics of mRNA synthesis). We are continuing the analysis of "immune interferon", i.e., antiviral activity produced during stimulation of sensitized mononuclear white blood cells with tuberculin-PPD. Our data so far show clearly that this material is completely distinct from Le and F interferons. We expect significant progress in this work in the next year.